James Harris IV also left his car key fob at the muddy site near Amierah Roberson’s lifeless body and asked acquaintances to pick him up on Saturday so he could get a second set of keys to his car, Cook County prosecutors said.

Police Question Slain Girl's Mother, Boyfriend

Boyfriend says he left girl unattended in car, came back to find her gone. Charlie Wojciechowski reports. (Published Monday, March 17, 2014)

“I f----- up, I f----- up. I lost my keys in the woods,” Harris allegedly told some people who noticed he had a bag that smelled liked gasoline, Assistant State’s Attorney Robert Mack said Thursday.

Inside the bag was child’s clothing, prosecutors said.

The driver who picked Harris up saw a lot of mud on Harris’ shoes and at the bottom of his pants, Mack said.

About 3:25 p.m. Sunday — 90 minutes before Harris allegedly reported the 19-month-old missing — several residents discovered her body near a dilapidated factory in the 14000 block of South Normal in Riverdale.

Amierah died of blunt force trauma to her head, according to the Cook County Medical Examiner’s Office. It was determined her burns were inflicted after she died, Mack said.

Harris allegedly admitted he took the child’s body to woods and burned her, prosecutors said. Initially, he had claimed she died from an accidental fall from the bed.

But police found blood on sheets in Harris’ bedroom as well as blood in the hallway outside the room where Amierah slept. Harris was supposed to have been watching the girl since Friday when her mother left for work, Mack said. The child’s mother had not seen her since then, Mack said.

When the girl’s mother was driving back to the couple’s apartment Sunday night, she spoke with Harris about their plans to eat out that night, Mack said.

Harris told his girlfriend to drive to the back of the apartment, in the 3500 block of South Rhodes, to pick him and Amierah up, Mack said.

However, Harris called his girlfriend back a little while after that to tell her that the child disappeared while they were waiting, Mack said.

Harris allegedly said Amierah was walking behind him but when he turned around, she was gone.

Harris, who turned 24 on Thursday, was ordered held without bond.

A defense attorney said Harris works with the disabled and previously worked as a janitor for the Chicago Board of Education.